The Commission, led by Lord Burns, makes three suggestions to Welsh Ministers. The first is to remove a variable speed limit from junctions 24 to 28 and replace it with an average speed control set to 50mph.

Recommendation two is to provide additional lane guidance on the westbound approach to the Brynglas tunnels and use physical measures to prevent late lane changes; and a third is to provide additional traffic officer support on the route.

These suggestions were made following the First Minister’s announcement in June not to proceed with a £1.4Bn project to build a 23km dual three lane relief road to the south of Newport; the so called ‘Black Route’ option.

Yesterday’s report points out that there is “clearly an acute congestion problem” on this stretch of the M4, with peak flows that include a significant degree of commuting. At its worst, the report adds, drivers face median speeds of between 20 and 30mph when travelling westbound towards the tunnels in the early evening. Up to 5000 vehicles an hour use the M4 near Newport at peak times.

The Commission says that its three fast track measures could be implemented for between £1M and £2M. Future recommendations set out include improving public transport for journeys between Cardiff, Newport and Bristol; options for a commuter cycling route from Cardiff to Newport; and greater priority for buses on surrounding roads.

But the Road Haulage Association’s policy director Duncan Buchanan described the fast track improvements as a series of “half baked measures”. “The M4 is a major strategic corridor for south Wales; it needs a bypass,” he said. “Half hearted attempts at managing demand are not going to cut it. It is vital for the businesses of south Wales to have good access to markets.”

Welsh Assembly Member for Newport West, Jayne Bryant was more supportive of the proposals. “Residents in Newport know that congestion on the M4 affects many more than just those travelling on it,” she said. “Whenever there is an accident on the M4, it is the roads outside our schools and homes that become gridlocked.

“The Commission and Welsh Government must act quickly and decisively. This significant problem needs ambitious but realistic solutions to make a real difference.”

(Photograph: Arup)